<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <link rel="stylesheet" href="meiti1.css" media="screen and (min-width:400px)">
    <link rel="stylesheet" href="meiti2.css" media="screen and (min-width:900px)">
    <title>不同屏幕引入不同css</title>
</head>
<body>
    <div>
        <p>第一个</p>
        <p>第二个</p>
    </div>
</body>
</html>